ICTSD Outputs and Activities on Biotechnology, Trade and Sustainble Development

Biotechnology: Addressing Key Trade and Sustainability Issues

B.1 Environmental, health-related and socio-economic considerations

Q2 Are GMOs harmful to the environment?

Existing evidence on the environmental impacts of GMO production does not yield proof of systemic adverse effects of the technology; however, similarly to the above-mentioned health concerns, some argue that not enough long-term studies have been carried out to lay to rest the various concerns that have been highlighted. In particular, many suggest that there is a need for an appreciation and study of the distinct environmental conditions that prevail in different parts of the world, including the ecosystems and soils in tropical, biodiversity-rich developing countries. It has also been stressed that efforts to assess the adverse impacts of GM crops must use conventional agricultural crops as the frame of reference or counterfactual.

GM crops can have two types of environmental impacts, namely a direct impact that derives from the GMO itself and indirect impacts that stem from the different management choices that the new
crop offers to the farmer.

Transfer of genes within species occurs naturally in the wild and in agricultural fields. In the context of GM crops, however, such gene transfer poses unique challenges because of the possible transfer
of transgenic DNA to non-modified plants. Such transfer would decrease the ability to control or regulate the spread of modified crops, and could affect biodiversity or cultural and social values (see Biotech Headline 2). Environmental advocates have cautioned that the transfer of genes from GM plants which have been genetically engineered to withstand herbicide applications could lead to the creation of ‘superweeds’ if the genes were taken up by related wild varieties of the same species. They warn that these ‘superweeds’ could be more difficult to kill, require more or stronger herbicides and could become invasive with adverse effects on agricultural biodiversity. A related concern is that GM plants themselves will become weeds, or could become invasive (Conner et al., 2003) (see also Q3).

BIOTECH HEADLINE 2: Mexican Maize

In October 2000, Ignacio Chapela and David Quist, researchers from the University of California at Berkeley’s College of Natural Resources, found transgenic DNA in maize grown in a remote area in the state of Oaxaca, Mexico. The Mexican government subsequently performed and in September 2001 released its own research confirming that, despite a moratorium on environmental release of GM maize in Mexicosince 1998, transgenic DNA had in fact made its way into Mexican maize landraces. In November 2001, Chapela and Quist published their research findings in the scientific journal Nature. The discovery ignited a controversy fuelled by the fact that Oaxaca is the so-called ‘centre of origin and diversity’ of maize, where it was domesticated from a weed named teosinte hundreds of years ago.

Environmentalists, farmers and local communities from Mexico and around the world asked how the local races became contaminated and questioned what the potential implications could be for the local communities and genetic diversity. Greenpeace, the ETC Group and other international civil society groups suggested that permanent loss of biodiversity may result, and local communities made links between the contamination and systemic political problems in rural areas. As a result, in April 2002, twenty-one indigenous communities from Oaxaca and three Mexican environmental groups petitioned the North American Commission for Environmental Cooperation (CEC) to assess the impacts of transgenic contamination of Mexican maize races. The CEC was created under the North American Agreement on Environmental Cooperation (NAAEC), an environmental side agreement to the North American Free Trade Agreement (NAFTA) between Mexico, Canada and the US.

The final CEC report, which was released in November 2004, traced the arrival of the GMOs in Oaxaca back to imports of maize from the US, where GM maize makes up approximately one-third of the maize crop and is not segregated from non-modified maize. Although the maize was only intended for consumption,
small-scale farmers planted the seeds. The report concludes that “there is no reason to expect that a transgene would have any greater or lesser effect on the genetic diversity of landraces or teosinte than other genes from similarly used modern cultivars”, suggesting that, from a scientific point of view,
transgenic maize does not threaten genetic diversity more than other methods of modern agriculture such as hybridisation. At the same time, the report stresses the cultural, symbolic and spiritual values of maize for many Mexicans, in particular the campesinos (or small-holder farmers) who “perceive GM maize as a
direct threat to political autonomy, cultural identity, personal safety and biodiversity”. The report adds “That sense of harm is independent of its scientifically studied potential or actual impact upon human health, genetic diversity, and the environment”.

Based on these concerns, and using a precautionary approach, the CEC report recommends that the GM maize planting moratorium should be continued and strengthened “by minimising the import of living transgenic maize grain from countries that grow transgenic maize commercially”. The US and Canada
issued strong public statements criticising the report and, in particular, what they regard as a contradiction between the scientific key findings and the recommendations. The publication of a new study in the Proceedings of the National Academy of Sciences in August 2005, showing no evidence of GMOs in more than 150,000 seeds taken from 870 plants in Oaxaca in 2003 and 2004 has, for now, calmed demands for measures to be taken.

Sources: CEC (2004); Ortiz-Garcia et al. (2005); Quist and Chapela (2001).

Gene flow from plants which have been genetically modified to produce pharmaceutical, chemical or industrial compounds could lead to the inadvertent spread of chemical compounds or medicines to soils, ecosystems and other plants. For example, in 2002, seeds from plants genetically modified to generate an animal vaccine germinated in the field from which they had earlier been harvested in the US, and mixed with soybeans that were subsequently grown on the land (Cohen, 2002). The soy was destroyed as the impacts of the vaccine on human health and the environment were unknown, and because ProdiGene – the Texas-based biotech company that had developed the GM maize – had not taken human consumption or environmental release into account in its risk assessment. However, given the unique nature of these plants, most regulators and actors in these industries agree that they need to be carefully segregated to prevent gene transfer to other crops and to the environment (Nuffield Council, 2004). Research on the environmental effects of these crops is in its infancy.

Genetic Use Restriction Technologies (GURTS) have been proposed by the biotech industry as a possible means to prevent unintended gene flow. GURTS can be used to genetically alter seeds to be sterile and thus prevent cross-fertilisation. The technology – dubbed ‘terminator technology’ by its critics – has attracted fierce criticism from environment, farmer and indigenous groups who warn that inhibiting a plant’s ability to reproduce could have adverse effects on rural livelihoods by preventing reuse of the seeds by farmers and on biodiversity by risking to transfer the trait to wild varieties. As a result, a de facto moratorium on field trials of GURTS was instituted by the Parties to the CBD in 2000 when countries recommended that “products incorporating such technologies should not be approved by Parties for field testing […] and for commercial use” until potential environmental and socio-econoimc impacts have been assessed (CBD, 2000).

GM crops can also have direct impacts on non-target species that consume them or their pollen. Crops which use Bacillus thuringiensis, a soil bacterium that kills many of the worm-like insects that destroy crops, is a case in point. While Bt saves the crop from pests that destroy the crop, it could also hurt other harmless worm-like insects that are found in the fields (see Biotech Headline 3). There is also the possibility that insects will become immune to the Bt toxin since such resistance would provide them with an evolutionary advantage in the presence of widespread Bt use. This could have adverse longterm effects on the invasiveness of these insects in the environment and on farms, because use of Bt – including through sprays and non-GM methods – is one of the most effective, cheapest and least environmentally harmful ways to tackle the spread of pests. This problem has not emerged thus far – possibly owing to the requirement in many countries to have small areas of non-Bt plants (“refuges”) near any Bt fields to minimise evolutionary advantages any Bt-resistant insects would have (IFATPC, 2004).

BIOTECH HEADLINE 3: Monarch Butterflies

On 20 May 1999, the journal Nature published research by leading scientists at Cornell University showing that monarch butterfly larvae that ate milkweed leaves coated with pollen from GM maize ate less, grew more slowly and suffered a higher mortality rate than those that ate non-coated leaves. The larvae in
question are small caterpillars that grow into the endangered and popular monarch butterflies, and the suggestion that they could be jeopardised by genetically modified Bt maize raised widespread concern.

Several studies released after the initial report have shown, however, that the actual risk posed to monarch butterflies by Bt maize was minimal. Bt is inserted into maize through genetic modification because it is selectively toxic to lepidopteran (larval or wormlike) insects. While the monarch butterfly larvae is such an
insect, and was thus affected by consuming pollen from Bt maize in the lab, scientists concluded that under ‘real world’ conditions butterfly larvae are unlikely to encounter Bt maize pollen in nature. Butterfly larvae feed on milkweed, a weed which farmers keep out from the fields of agricultural crops such as maize. Monarch butterflies in particular prefer to eat milkweed near open meadows, ditches and pastures where they fly and deposit their larvae at a distance from the fields. Maize pollen cannot reach the milkweed plants in the ditches on which the larvae like to feed because it is too heavy. Field studies in Iowa and in agriculture departments of a number of US universities, along with a 2001 report from the US Environmental Protection Agency (USEPA), confirmed that the lack of milkweed in maize fields and the preference of butterflies for milkweed far from maize fields decrease the presence of Bt pollen in butterfly diets. They also pointed out that maize pollen is released in five to ten-day intervals when most butterfly larvae are not present because of migratory patterns, and that monarch butterflies do not like to eat pollen and tend to avoid pollen-tainted milkweed leaves, Bt or not. For all these reasons, during field trials scientists found that it was rare to have a combination of maize, pollen, milkweed and monarch butterfly larvae. Biotech supporters also stress that even if this combination were to occur, factors such as habitat destruction and the use of broad spectrum herbicides pose far greater threats to the Monarchs.

Sources: Losey et al. (1999); USDA (2004).

In addition, GM crops change the options that are available to farmers for pest and weed management. The use of the new crops can lead to farming practices that affect the agricultural environment,
including different kinds and quantities of pesticides and herbicides, resulting in indirect effects of the new crops’ characteristics on the surrounding environment.

GM crops can change the way herbicides are applied to the crop (FAO, 2004). A single, broad-spectrum herbicide, such as glyphosate, is often sprayed on plants that have been genetically modified to be tolerant to herbicides in order to kill the weeds that surround the plants. Glyphosate has been advocated as a relatively benign herbicide since it rapidly degrades in the soil and has a low level of toxicity. Herbicide-tolerant crops are also claimed to require fewer applications of herbicides than conventional crops. However, whether the GM plants reduce overall herbicide use and persistence
in the soil depends on a variety of factors, such as the suitability of the plant variety to the region, the extent of pre-GM investment in chemical herbicides and fertilizers, and the adaptation of pests and weeds to the treatment. Changes in herbicide application can also have impacts on non-target weed and plant life and the insects and animals that eat them. The effectiveness of the new herbicide in killing weeds (while allowing the crop itself to survive) can eliminate most weed cover and thereby reduce soil and agricultural biodiversity and harm non-target species that feed on these weeds. The
largest agricultural biodiversity study to date, known as the UK Farm Scale Evaluations, concluded that while the use of GM crops does change the mix of weeds that survive herbicides, the impacts
on agricultural biodiversity vary between crops and the particular herbicides used, and are within the normal scope of biodiversity impact variation within crops (see Biotech Headline 4).

More broadly, there are fears that adoption of GM plant varieties could encourage a tendency towards monocropping, intensive farming and mechanisation of agriculture with adverse impacts on biodiversity. Supporters of GM crops argue that in fact it could do the opposite by reducing the need for chemical inputs and mechanised operations, with positive impacts on water supplies, pesticide use, pesticide residues, farmer health and food safety. For example, the fact that herbicide-tolerant plants need not be ploughed around for removal of weeds means that ‘no-till’ practices can be adopted, which in turn can preserve soil, prevent desertification and stripping of soil nutrients and reduce greenhouse gas emissions. However, it also needs to be borne in mind that, particularly in developing countries, GM crops and their accompanying herbicide or pesticide treatments might become a substitute for what has so far been herbicide and pesticide-free production, rather than an alternative to herbicide and pesticideintensive production as it is in developed countries.

The environmental implications of GM animals have also been raised. It is feared that the increased use of a few uniform GM animals could reduce animal biodiversity, and that the spread of genes from
GM animals would be difficult to control, owing to the animals’ mobility and reproductive patterns. Furthermore, there are concerns that unintended effects of genetic modification, similar to those described above for plants, could lead to novel changes to the animal physiology that could be difficult to predict, anticipate or address.

In this context, transgenic fish have raised particular concerns (Pew Initiative, 2003). It is feared that GM fish might escape from fish farms and spread novel traits into the ecosystem by breeding with wild
relatives, thereby impacting on marine biodiversity. Transgenic fish that escape into natural ecosystems could also be an environmental nuisance by becoming an invasive species. Scientists are attempting to reduce these risks by sterilising transgenic fish (Pew Initiative, 2003).

Research is also under way to genetically modify insects in order to reduce invasive populations, such as fruit flies, through selective sterilisation. There are also more ambitious projects to change other
characteristics of insects to make them less problematic – for example, to decrease their tendency to spread viruses. While such changes have been advocated by some as a means of ensuring human and in some cases animal health, the complicated relationship between insects, bacteria, animals and ecosystems, along with the difficulty in controlling the spread of insects, has raised concerns about the unintended spread of GM insects and the potential implications on their invasiveness and impacts. As such, no GM insects have been released to date (Pew Initiative, 2004).

At the same time, the most promising field of animal biotechnology – the use of biotechnology to develop vaccines and reproductive techniques – could in fact improve animal health and diversity (MacKenzie, 2005).

BIOTECH HEADLINE 4: UK Farm Scale Evaluations

In 1999, the UK government asked an independent consortium of researchers to investigate how growing four types of herbicide-tolerant GM crops might affect the abundance and diversity of farmland wildlife compared with growing conventional varieties of the same crops. The resulting study, called the Farm Scale Evaluations (FSE), lasted five years, cost around GBP6 million and was the largest field experiment ever conducted on farmland ecology. The research pointed to differences in impacts on weed, insect and other farm wildlife populations between GM and non-GM crops. The report found that these differences could be attributed to the type and way herbicides were applied to the GM and non-modified crops rather than the genetic modification itself.

More specifically, it was found that GM beet and spring rape (canola) crops had fewer weeds, weed seeds, bees and butterflies, but more springtails (an insect that feeds on decaying plants). On the other hand, growing GM maize was better for many groups of wildlife than conventional maize because the GM crops had more weeds, seeds, bees and butterflies and springtails. Regarding winter rape, the GM and conventional crops had the same number of weeds overall. The GM crop was found to have more grass weeds and seeds but fewer broad-leaved weeds and seeds, resulting in fewer butterflies and bees, who feed predominantly on broad-leaved weed seeds, but more springtails.

Anti-GM campaigners, along with the UK and European media, hailed the study as proof that GM crops should be abandoned. “These results are another good reason to abandon all plans for growing GM oilseed rape in the UK,” GeneWatch Director Sue Mayer said. Others suggested that the results showed that GM crops do not pose a threat in themselves to farm biodiversity; rather, GM-conventional comparisons test the relative impact of different herbicide uses given that GM crops offer new herbicide choices. They also pointed out that in all four cases there was only one herbicide spray for the GM crops, compared to multiple sprayings for conventional crops, delivering positive environmental impacts given that herbicides can also damage the environment in the long term. Also, they noted that differences in impacts on biodiversity were greater among the four types of crops than between GM and conventional varieties of one crop, implying that the choice of crop – along with the type of crop rotation, pesticide use and agricultural intensity – may have more significant impacts on farmland wildlife than the different herbicide uses resulting from GM crops.

Sources: AgBioWorld (2003); GeneWatch (2005); www.defra.gov.uk/environment/gm/fse/.